Hilz, M J; Liu, M; Koehn, J; Wang, R; Ammon, F; Flanagan, S R; Hosl, K M
Valsalva maneuver unveils central baroreflex dysfunction with altered blood pressure control in persons with a history of mild traumatic brain injury Journal Article
In: BMC Neurology, vol. 16, pp. 61, 2016.
Abstract | BibTeX | Tags: *Autonomic Nervous System Diseases/pp [Physiopatho, *Baroreflex, *Blood Pressure, *Brain Concussion/pp [Physiopathology], *Valsalva Maneuver, adult, Case-Control Studies, Female, Heart Rate/ph [Physiology], Humans, Male, Respiration
@article{Hilz2016,
title = {Valsalva maneuver unveils central baroreflex dysfunction with altered blood pressure control in persons with a history of mild traumatic brain injury},
author = {Hilz, M J and Liu, M and Koehn, J and Wang, R and Ammon, F and Flanagan, S R and Hosl, K M},
year = {2016},
date = {2016-01-01},
journal = {BMC Neurology},
volume = {16},
pages = {61},
abstract = {BACKGROUND: Patients with a history of mild TBI (post-mTBI-patients) have an unexplained increase in long-term mortality which might be related to central autonomic dysregulation (CAD). We investigated whether standardized baroreflex-loading, induced by a Valsalva maneuver (VM), unveils CAD in otherwise healthy post-mTBI-patients. METHODS: In 29 healthy persons (31.3+/-12.2 years; 9 women) and 25 post-mTBI-patients (35.0+/-13.2 years, 7 women, 4-98 months post-injury), we monitored respiration (RESP), RR-intervals (RRI) and systolic blood pressure (BP) at rest and during three VMs. At rest, we calculated parameters of total autonomic modulation [RRI-coefficient-of-variation (CV), RRI-standard-deviation (RRI-SD), RRI-total-powers], of sympathetic [RRI-low-frequency-powers (LF), BP-LF-powers] and parasympathetic modulation [square-root-of-mean-squared-differences-of-successive-RRIs (RMSSD), RRI-high-frequency-powers (HF)], the index of sympatho-vagal balance (RRI LF/HF-ratios), and baroreflex sensitivity (BRS). We calculated Valsalva-ratios (VR) and times from lowest to highest RRIs after strain (VR-time) as indices of parasympathetic activation, intervals from highest systolic BP-values after strain-release to the time when systolic BP had fallen by 90 % of the differences between peak-phase-IV-BP and baseline-BP (90 %-BP-normalization-times), and velocities of BP-normalization (90 %-BP-normalization-velocities) as indices of sympathetic withdrawal. We compared patient- and control-parameters before and during VM (Mann-Whitney-U-tests or t-tests; significance: P\<0.05). RESULTS: At rest, RRI-CVs, RRI-SDs, RRI-total-powers, RRI-LF-powers, BP-LF-powers, RRI-RMSSDs, RRI-HF-powers, and BRS were lower in patients than controls. During VMs, 90 %-BP-normalization-times were longer, and 90 %-BP-normalization-velocities were lower in patients than controls (P\<0.05). CONCLUSIONS: Reduced autonomic modulation at rest and delayed BP-decrease after VM-induced baroreflex-loading indicate subtle CAD with altered baroreflex adjustment to challenge. More severe autonomic challenge might trigger more prominent cardiovascular dysregulation and thus contribute to increased mortality risk in post-mTBI-patients.},
keywords = {*Autonomic Nervous System Diseases/pp [Physiopatho, *Baroreflex, *Blood Pressure, *Brain Concussion/pp [Physiopathology], *Valsalva Maneuver, adult, Case-Control Studies, Female, Heart Rate/ph [Physiology], Humans, Male, Respiration},
pubstate = {published},
tppubtype = {article}
}
Hilz, M J; Liu, M; Koehn, J; Wang, R; Ammon, F; Flanagan, S R; Hosl, K M
Valsalva maneuver unveils central baroreflex dysfunction with altered blood pressure control in persons with a history of mild traumatic brain injury Journal Article
In: BMC Neurology, vol. 16, pp. 61, 2016.
@article{Hilz2016,
title = {Valsalva maneuver unveils central baroreflex dysfunction with altered blood pressure control in persons with a history of mild traumatic brain injury},
author = {Hilz, M J and Liu, M and Koehn, J and Wang, R and Ammon, F and Flanagan, S R and Hosl, K M},
year = {2016},
date = {2016-01-01},
journal = {BMC Neurology},
volume = {16},
pages = {61},
abstract = {BACKGROUND: Patients with a history of mild TBI (post-mTBI-patients) have an unexplained increase in long-term mortality which might be related to central autonomic dysregulation (CAD). We investigated whether standardized baroreflex-loading, induced by a Valsalva maneuver (VM), unveils CAD in otherwise healthy post-mTBI-patients. METHODS: In 29 healthy persons (31.3+/-12.2 years; 9 women) and 25 post-mTBI-patients (35.0+/-13.2 years, 7 women, 4-98 months post-injury), we monitored respiration (RESP), RR-intervals (RRI) and systolic blood pressure (BP) at rest and during three VMs. At rest, we calculated parameters of total autonomic modulation [RRI-coefficient-of-variation (CV), RRI-standard-deviation (RRI-SD), RRI-total-powers], of sympathetic [RRI-low-frequency-powers (LF), BP-LF-powers] and parasympathetic modulation [square-root-of-mean-squared-differences-of-successive-RRIs (RMSSD), RRI-high-frequency-powers (HF)], the index of sympatho-vagal balance (RRI LF/HF-ratios), and baroreflex sensitivity (BRS). We calculated Valsalva-ratios (VR) and times from lowest to highest RRIs after strain (VR-time) as indices of parasympathetic activation, intervals from highest systolic BP-values after strain-release to the time when systolic BP had fallen by 90 % of the differences between peak-phase-IV-BP and baseline-BP (90 %-BP-normalization-times), and velocities of BP-normalization (90 %-BP-normalization-velocities) as indices of sympathetic withdrawal. We compared patient- and control-parameters before and during VM (Mann-Whitney-U-tests or t-tests; significance: P\<0.05). RESULTS: At rest, RRI-CVs, RRI-SDs, RRI-total-powers, RRI-LF-powers, BP-LF-powers, RRI-RMSSDs, RRI-HF-powers, and BRS were lower in patients than controls. During VMs, 90 %-BP-normalization-times were longer, and 90 %-BP-normalization-velocities were lower in patients than controls (P\<0.05). CONCLUSIONS: Reduced autonomic modulation at rest and delayed BP-decrease after VM-induced baroreflex-loading indicate subtle CAD with altered baroreflex adjustment to challenge. More severe autonomic challenge might trigger more prominent cardiovascular dysregulation and thus contribute to increased mortality risk in post-mTBI-patients.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Hilz, M J; Liu, M; Koehn, J; Wang, R; Ammon, F; Flanagan, S R; Hosl, K M
Valsalva maneuver unveils central baroreflex dysfunction with altered blood pressure control in persons with a history of mild traumatic brain injury Journal Article
In: BMC Neurology, vol. 16, pp. 61, 2016.
Abstract | BibTeX | Tags: *Autonomic Nervous System Diseases/pp [Physiopatho, *Baroreflex, *Blood Pressure, *Brain Concussion/pp [Physiopathology], *Valsalva Maneuver, adult, Case-Control Studies, Female, Heart Rate/ph [Physiology], Humans, Male, Respiration
@article{Hilz2016,
title = {Valsalva maneuver unveils central baroreflex dysfunction with altered blood pressure control in persons with a history of mild traumatic brain injury},
author = {Hilz, M J and Liu, M and Koehn, J and Wang, R and Ammon, F and Flanagan, S R and Hosl, K M},
year = {2016},
date = {2016-01-01},
journal = {BMC Neurology},
volume = {16},
pages = {61},
abstract = {BACKGROUND: Patients with a history of mild TBI (post-mTBI-patients) have an unexplained increase in long-term mortality which might be related to central autonomic dysregulation (CAD). We investigated whether standardized baroreflex-loading, induced by a Valsalva maneuver (VM), unveils CAD in otherwise healthy post-mTBI-patients. METHODS: In 29 healthy persons (31.3+/-12.2 years; 9 women) and 25 post-mTBI-patients (35.0+/-13.2 years, 7 women, 4-98 months post-injury), we monitored respiration (RESP), RR-intervals (RRI) and systolic blood pressure (BP) at rest and during three VMs. At rest, we calculated parameters of total autonomic modulation [RRI-coefficient-of-variation (CV), RRI-standard-deviation (RRI-SD), RRI-total-powers], of sympathetic [RRI-low-frequency-powers (LF), BP-LF-powers] and parasympathetic modulation [square-root-of-mean-squared-differences-of-successive-RRIs (RMSSD), RRI-high-frequency-powers (HF)], the index of sympatho-vagal balance (RRI LF/HF-ratios), and baroreflex sensitivity (BRS). We calculated Valsalva-ratios (VR) and times from lowest to highest RRIs after strain (VR-time) as indices of parasympathetic activation, intervals from highest systolic BP-values after strain-release to the time when systolic BP had fallen by 90 % of the differences between peak-phase-IV-BP and baseline-BP (90 %-BP-normalization-times), and velocities of BP-normalization (90 %-BP-normalization-velocities) as indices of sympathetic withdrawal. We compared patient- and control-parameters before and during VM (Mann-Whitney-U-tests or t-tests; significance: P\<0.05). RESULTS: At rest, RRI-CVs, RRI-SDs, RRI-total-powers, RRI-LF-powers, BP-LF-powers, RRI-RMSSDs, RRI-HF-powers, and BRS were lower in patients than controls. During VMs, 90 %-BP-normalization-times were longer, and 90 %-BP-normalization-velocities were lower in patients than controls (P\<0.05). CONCLUSIONS: Reduced autonomic modulation at rest and delayed BP-decrease after VM-induced baroreflex-loading indicate subtle CAD with altered baroreflex adjustment to challenge. More severe autonomic challenge might trigger more prominent cardiovascular dysregulation and thus contribute to increased mortality risk in post-mTBI-patients.},
keywords = {*Autonomic Nervous System Diseases/pp [Physiopatho, *Baroreflex, *Blood Pressure, *Brain Concussion/pp [Physiopathology], *Valsalva Maneuver, adult, Case-Control Studies, Female, Heart Rate/ph [Physiology], Humans, Male, Respiration},
pubstate = {published},
tppubtype = {article}
}